Electrodes, compositions, and devices having high structure carbon blacks

ABSTRACT

An electrode for an energy storage device includes carbon black particles having (a) a Brunauer-Emmett-Teller (BET) surface area ranging from 70 to 120 m 2 /g; (b) an oil absorption number (OAN) ranging from 180 to 310 mL/100 g; (c) a surface energy less than or equal to 15 mJ/m 2 ; and (d) either an L a  crystallite size less than or equal to 29 Å, or a primary particle size less than or equal to 24 nm.

RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(e) to U.S. Prov.App. No. 62/332,142, filed May 5, 2016, hereby incorporated byreference.

FIELD OF THE INVENTION

The invention relates to electrodes, compositions, and devices includinghigh structure carbon blacks.

BACKGROUND

Lithium-ion batteries are commonly used electrical energy sources for avariety of applications, such as electronic devices and electricvehicles. A lithium-ion battery typically includes a negative electrode(e.g., graphite) and a positive electrode (described below) that allowlithium ions and electrons to move to and from the electrodes duringcharging and discharging. An electrolyte solution in contact with theelectrodes provides a conductive medium in which the ions can move. Toprevent direct reaction between the electrodes, an ion-permeableseparator is used to physically and electrically isolate the electrodes.When the battery is used as an energy source for a device, electricalcontact is made to the electrodes, allowing electrons to flow throughthe device to provide electrical power, and lithium ions to move throughthe electrolyte from one electrode to the other electrode.

The positive electrode typically includes a conductive substratesupporting a mixture (e.g., applied as a paste) having at least anelectroactive material, a binder, and a conductive additive. Theelectroactive material, such as a lithium transition metal oxide, iscapable of receiving and releasing lithium ions. The binder, such aspolyvinylidene fluoride, is used to provide mechanical integrity andstability to the electrode. Typically, since the electroactive materialand the binder are electrically poorly conducting or insulating, theconductive additive (e.g., graphite and carbon black) is added toenhance the electrical conductivity of the electrode. The conductiveadditive and the binder, however, are generally not involved inelectrochemical reactions that generate electrical energy, so thesematerials can negatively affect certain performance characteristics(e.g., capacity and energy density) of the battery since theyeffectively lower the amount of electroactive material that can becontained in the positive electrode.

SUMMARY

In one aspect, the invention features highly structured carbon blackparticles (or carbon blacks), and applications of such carbon blacks inenergy storage applications, such as lithium-ion batteries. It has beenfound that such carbon blacks can be used in electrodes (e.g., positiveelectrodes of lithium-ion batteries) at relatively low loadings (i.e.,concentrations). As a result, for a given electrode volume, relativelymore electroactive material can be incorporated, thereby improving thebattery's performance (e.g., capacity, volumetric energy, and energydensity).

Furthermore, the highly structured carbon blacks described herein arecapable of providing processability benefits that can enhance theprocess used to manufacture the electrodes. For example, the highlystructured carbon blacks are easily dispersible. In the manufacturingprocess, less energy is needed to combine an easily dispersible carbonblack in an electrode formulation, thereby enhancing thecost-effectiveness and efficiency of the process. The highly structuredcarbon blacks described herein are also capable of providing aformulation with relatively low viscosity. As a result, the formulationcan be made with a high solids content, which means more electrodes canbe formed for a given formulation batch, and utilization is increased.

In another aspect, the invention features an electrode for an energystorage device, including carbon black particles having (a) aBrunauer-Emmett-Teller (BET) surface area ranging from 70 to 120 m²/g;(b) an oil absorption number (OAN) ranging from 180 to 310 mL/100 g; (c)a surface energy less than or equal to 15 mJ/m²; and (d) either an L_(a)crystallite size less than or equal to 29 Å, or a primary particle sizeless than or equal to 24 nm. The electrode can be included in an energystorage device, such as a lithium ion battery, a primary alkalinebattery, a primary lithium battery, a nickel metal hydride battery, asodium battery, a lithium sulfur battery, a lithium air battery, ahybrid battery-supercapacitor device, a metal-air battery, a flowbattery, or a supercapacitor.

In another aspect, the invention features a composition, includingcarbon black particles having (a) a BET surface area ranging from 70 to120 m²/g; (b) an OAN ranging from 180 to 310 mL/100 g; (c) a surfaceenergy less than or equal to 15 mJ/m²; and (d) either an L_(a)crystallite size less than or equal to 29 Å, or a primary particle sizeless than or equal to 24 nm. The composition can be in the form of adispersion, a dry powder, a slurry or a paste. A paste that has 4 wt %conductive carbon black can have a viscosity of less than 20 Pa-s atshear rate of 50 s⁻¹. The composition can further include anelectroactive material.

In another aspect, the invention features carbon black particles having(a) a BET surface area ranging from 70 to 120 m²/g; (b) an OAN rangingfrom 180 to 310 mL/100 g; (c) a surface energy less than or equal to 15mJ/m²; and (d) either an L_(a) crystallite size less than or equal to 29Å, or a primary particle size less than or equal to 24 nm.

In another aspect, the invention features a method, including heattreating carbon black particles to form a heat-treated carbon blackparticles having (a) a BET surface area ranging from 70 to 120 m²/g; (b)an OAN ranging from 180 to 310 mL/100 g; (c) a surface energy less thanor equal to 18 mJ/m²; and (d) either an L_(a) crystallite size less thanor equal to 29 Å, or a particle size less than or equal to 24 nm. Theheat treating can be performed at a temperature ranging from 1400° C. to1600° C. in an inert atmosphere.

Embodiments of one or more aspects may include one or more of thefollowing features. The carbon black particles have both an L_(a)crystallite size less than or equal to 29 Å, and a particle size lessthan or equal to 24 nm. The carbon black particles have a BET surfacearea ranging from 80 to 110 m²/g, or from 70 to 100 m²/g. The carbonblack particles have an OAN number ranging from 200 to 285 mL/100 g, orfrom 200 to 260 mL/100 g. The carbon black particles have either anL_(a) crystallite size less than or equal to 27 Å, or a particle sizeless than or equal to 22 nm. The carbon black particles have either anL_(a) crystallite size less than or equal to 29 Å, or a particle sizeless than or equal to 20 nm. The carbon black particles have an L_(a)crystallite size less than or equal to 29 Å, or less than or equal to 27Å, or from 25 Å to 29 Å. The electrode of any one of claims 1-11,wherein the carbon black particles have a particle size less than orequal to 24 nm, or less than or equal to 22 nm, or from 12 to 24 nm. Thecarbon black particles have a surface energy less than or equal to 10mJ/m², or from 1 to 10 mJ/m². The electrode carbon black particles havea % crystallinity (I_(G)/I_(G+D)) less than or equal to 45%, or 35% to45%, as determined by Raman spectroscopy. The carbon black particleshave an oxygen content of less than or equal to 1 wt %. The carbon blackparticles have a dispersability of less than one micron (D₅₀ by volume).The carbon black particles have a ratio of statistical thickness surfacearea to BET surface area (STSA:BET) greater than 0.95:1.

Other aspects, features, and advantages of the invention will beapparent from the description of the embodiments thereof and from theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plot of particle size distributions for formulationsincluding 5.7 wt % carbon black (or acetylene black) and 4.3 wt % PVDFin NMP after 20 minutes of milling in an SPEX® 8000M mixer/mill, inaccordance to Example 2.

FIG. 2 is a plot showing sheet resistance for electrodes, compressed toa density of 2.5 g/cm³ prior to measurement, having various conductivecarbon additives at 4 wt % (left) and 2 wt % (right) loading.

FIG. 3 shows discharge curves of for coin cells with various conductivecarbon additives (CCA) at 2 wt % loading as a function of C-rate. Thecathode composition was NCM 111:CCA:PVDF=96.5:2:1.5.

FIG. 4 shows discharge curves for coin cells with various conductivecarbon additives at 4 wt % loading as a function of C-rate. The cathodecomposition is NCM 111:CCA:PVDF=93:4:3.

FIG. 5 is a plot of the DC-IR component of the total resistance as afunction of state of charge for cells having different carbon conductiveadditives at 2 wt % loading (NCM 111:CCA:PVDF=96.5:2:1.5).

FIG. 6 is a plot of the ionic component of the total resistance as afunction of state of charge for cells having different carbon conductiveadditives at 2 wt % loading (NCM 111:CCA:PVDF=96.5:2:1.5).

FIG. 7 is a plot of the DC-IR component of the total resistance as afunction of state of charge for cells having different carbon conductiveadditives at 4 wt % loading (NCM 111:CCA:PVDF=93:4:3).

FIG. 8 is a plot of the ionic component of the total resistance as afunction of state of charge for the cells having different carbonconductive additives at 4 wt % loading (NCM 111:CCA:PVDF=93:4:3).

FIG. 9 summarizes evaluation results from fast charging tests of twoconductive additives.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Described below are high structure carbon black particles, methods ofmaking the particles, compositions including the particles, andapplications of the particles in energy storage devices (e.g.,lithium-ion batteries).

The high structure carbon black particles can generally be characterizedby their (1) Brunauer-Emmett-Teller (BET) total surface areas, (2)structures, and (3) sizes of the crystallites and/or sizes of theprimary particles. Additionally, the particles can be furthercharacterized by their surface energies, statistical thickness surfaceareas, and/or oxygen content, in any combination.

The carbon black particles have relatively low to intermediate totalsurface areas. Without being bound by theory, it is believed that,during use of a battery, there are chemical side reactions that canoccur within the battery that degrade its performance. Having particleswith lower surface areas can enhance the performance of the battery byproviding fewer surface sites where these unwanted side reactions canoccur. However, the surface areas of the particles should be balanced,i.e., high enough, so that the particles can sufficiently cover theelectroactive material and provide the desired electrode conductivity.In some embodiments, the carbon black particles have a BET surface arearanging from 70 to 120 m²/g. The BET surface area can have or include,for example, one of the following ranges: from 70 to 110 m²/g, or from70 to 100 m²/g, or from 70 to 90 m²/g, or from 70 to 80 m²/g, or from 80to 120 m²/g, or from 80 to 110 m²/g, or from 80 to 100 m²/g, or from 80or 90 m²/g, or from 90 to 120 m²/g, or from 90 to 110 m²/g, or from 90to 100 m²/g, or from 100 to 120 m²/g, or from 100 to 110 m²/g, or from110 to 120 m²/g. All BET surface area values disclosed herein refer to“BET nitrogen surface area” and are determined by ASTM D6556-10, theentirety of which is incorporated herein by reference.

The carbon black particles have relatively high oil absorption numbers(OANs), which are indicative of the particles' relatively highstructures, or volume-occupying properties. For a given mass, the highstructure carbon blacks can occupy more volume than other carbon blackshaving lower structures. When used as a conductive additive in a batteryelectrode, carbon blacks having relatively high OANs can provide acontinuously electrically-conductive network (i.e., percolate)throughout the electrode at relatively lower loadings. Consequently,more electroactive material can be used, thereby improving theperformance of the battery. In some embodiments, the carbon blacks haveOANs ranging from 180 to 310 mL/100 g. The OANs can have or include, forexample, one of the following ranges: from 180 to 290 mL/100 g, or from180 to 270 mL/100 g, or from 180 to 250 mL/100 g, or from 180 to 230mL/100 g, or from 200 to 310 mL/100 g, or from 200 to 300 mL/100 g, orfrom 200 to 290 mL/100 g, or from 200 to 285 mL/100 g, or from 200 to270 mL/100 g, or from 200 to 265 mL/100 g, or from 200 to 260 mL/100 g,or from 200 to 250 mL/100 g, or from 200 to 240 mL/100 g, or from 200 to230 mL/100 g, or from 200 to 220 mL/100 g, or from 210 to 310 mL/100 g,or from 210 to 300 mL/100 g, or from 210 to 290 mL/100 g, or from 210 to280 mL/100 g, or from 210 to 270 mL/100 g, or from 210 to 260 mL/100 g,or from 210 to 250 mL/100 g, or from 210 to 240 mL/100 g, or from 210 to230 mL/100 g, or from 220 to 310 mL/100 g, or from 220 to 300 mL/100 g,or from 220 to 290 mL/100 g, or from 220 to 280 mL/100 g, or from 220 to270 mL/100 g, or from 220 to 260 mL/100 g, or from 220 to 250 mL/100 g,or from 220 to 240 mL/100 g, or from 230 to 310 mL/100 g, or from 230 to290 mL/100 g, or from 230 to 270 mL/100 g, or from 230 to 260 mL/100 g,or from 230 to 250 mL/100 g, or from 240 to 310 mL/100 g, or from 240 to290 mL/100 g, or from 240 to 270 mL/100 g or from 240 to 260 mL/100 g.Other ranges within these ranges are possible. All OAN values citedherein are determined by the method described in ASTM D 2414-13a, usingepoxidized fatty acid ester (EFA) oil and Procedure B. The method ofASTM D 2414-13a is incorporated herein by reference.

The high structure carbon black particles generally have moderatecrystalline domain sizes and/or moderate degrees of crystallinity.Without being bound by theory, it is believed that certain domain sizesand/or crystallinities can enhance the conductivity and performance ofthe particles by reducing the electrical resistance that can occur whenelectrons move between different areas or phases of material. However,domain sizes that are too big and/or crystallinities that are too highcan degrade electrical conductivity since, it is believed, otherconducting mechanisms (e.g., holes) can be affected.

The crystalline domains can be characterized by an L_(a) crystallitesize, as determined by Raman spectroscopy. L_(a) is defined as43.5×(area of G band/area of D band). The crystallite size can give anindication of the degree of graphitization, where a higher L_(a) valuecorrelates with a higher degree of graphitization. Raman measurements ofL_(a) were based on Gruber et al., “Raman studies of heat-treated carbonblacks,” Carbon Vol. 32 (7), pp. 1377-1382, 1994, which is incorporatedherein by reference. The Raman spectrum of carbon includes two major“resonance” bands at about 1340 cm⁻¹ and 1580 cm⁻¹, denoted as the “D”and “G” bands, respectively. It is generally considered that the D bandis attributed to disordered sp² carbon, and the G band to graphitic or“ordered’ sp² carbon. Using an empirical approach, the ratio of the G/Dbands and an L_(a) measured by X-ray diffraction (XRD) are highlycorrelated, and regression analysis gives the empirical relationship:

L _(a)=43.5×(area of G band/area of D band),

in which L_(a) is calculated in Angstroms. Thus, a higher L_(a) valuecorresponds to a more ordered crystalline structure.

In some embodiments, the carbon black has an L_(a) crystallite size ofless than or equal to 35 Å, for example, from 25 Å to 35 Å. The L_(a)crystallite size can have or include, for example, one of the followingranges: from 25 to 33 Å, or from 25 to 31 Å, or from 25 to 29 Å, or from25 to 27 Å, or from 27 to 35 Å, or from 27 to 33 Å, or from 27 to 31 Å,or from 27 to 29 Å, or from 29 to 35 Å, or from 29 to 33 Å, or from 29to 31 Å, or from 31 to 35 Å, or from 31 to 33 Å, or from 33 to 35 Å. Incertain embodiments, the L_(a) crystallite size can be less than orequal to 33 Å, or less than or equal to 31 Å, or less than or equal to29 Å, or less than or equal to 27 Å.

The crystalline domains can be characterized by an L_(c) crystallitesize. The L_(c) crystallite size was determined by X-ray diffractionusing an X-ray diffractometer (PANalytical X'Pert Pro, PANalyticalB.V.), with a copper tube, tube voltage of 45 kV, and a tube current of40 mA. A sample of carbon black particles was packed into a sampleholder (an accessory of the diffractometer), and measurement wasperformed over angle (2θ) range of 10° to 80°, at a speed of 0.14°/min.Peak positions and full width at half maximum values were calculated bymeans of the software of the diffractometer. For measuring-anglecalibration, lanthanum hexaboride (LaB₆) was used as an X-ray standard.From the measurements obtained, the L_(c) crystallite size wasdetermined using the Scherrer equation: L_(c) (Å)=K*λ/(β*cos θ), where Kis the shape factor constant (0.9); λ is the wavelength of thecharacteristic X-ray line of Cu K_(α1) (1.54056 Å); β is the peak widthat half maximum in radians; and θ is determined by taking half of themeasuring angle peak position (2θ).

A higher L_(c) value corresponds to a more ordered crystallinestructure. In some embodiments, the carbon black has an L_(c)crystallite size of less than or equal to 27 Å, for example, from 15 Åto 27 Å. The L_(c) crystallite size can have or include, for example,one of the following ranges: from 15 to 25 Å, or from 15 to 23 Å, orfrom 15 to 21 Å, or from 15 to 19 Å, or from 15 to 17 Å, or from 17 to27 Å, or from 17 to 25 Å, or from 17 to 23 Å, or from 17 to 21 Å, orfrom 17 to 19 Å, or from 19 to 27 Å, or from 19 to 25 Å, or from 19 to23 Å, or from 19 to 21 Å, or from 21 to 27 Å, or from 21 to 25 Å, orfrom 21 to 23 Å, or from 23 to 27 Å, or from 23 to 25 Å, or from 25 to27 Å. In certain embodiments, the L_(c) crystallite size can be lessthan or equal to 25 Å, or less than or equal to 23 Å, or less than orequal to 21 Å, or less than or equal to 19 Å, or less than or equal to17 Å.

The carbon black particles can be described (in a simplified manner) asan aggregate of a number of smaller particles, which are referred to as“primary particles.” The carbon black aggregates can be, for example,assemblies of primary carbon black particles that are fused at thecontact points and cannot readily be separated by shearing. The size ofprimary particles in a carbon black particle can vary. The number ofprimary particles in the aggregate can also vary, for example, from fewto tens, or possibly hundreds. The number of primary particles and thearrangement of them in the carbon black aggregate not only dictate thesize of the carbon black aggregate but also the structure of the carbonblack. Without being bound by theory, it is believed that, for a givenmass of particles, those particles with small average primary particlesizes can more effectively cover the electroactive material because theparticles have a large number of contact points, thereby enhancing theperformance of the particles. The average primary particle size(P_(size)) can be, for example, less than 24 nm, for example, from 12 to24 nm. The average primary particle size can have or include, forexample, one of the following ranges: from 12 nm to 22 nm, or from 12 nmto 20 nm, or from 12 nm to 18 nm, or from 12 nm to 16 nm, or from 14 nmto 24 nm, or from 14 nm to 22 nm, or from 14 nm to 20 nm, or from 14 nmto 18 nm, or from 16 nm to 24 nm, or from 16 nm to 22 nm, or from 16 nmto 20 nm, or from 18 nm to 24 nm, or from 18 nm to 22 nm, or from 20 nmto 24 nm. In certain embodiments, the average primary particle size isless than or equal to 22 nm, or less than or equal to 19 nm, or lessthan or equal to 17 nm, or less than or equal to 15 nm, or less than orequal to 13 nm. The average primary particle size is determined by ASTMD3849-14a, the entirety of which is incorporated herein by reference.

Independent of the properties described above, the carbon blackparticles can have one or more of the following additional properties:statistical thickness surface area (STSA), STSA to BET surface arearatio, % crystallinity, surface energy, and/or oxygen content. Forinstance, the carbon black particles can have at least one, two, three,four, or more of the following properties. The carbon black particlescan have any combination of the following properties.

The carbon black particles can have statistical thickness surface areas(STSAs) that are substantially the same as the BET total surface areasdescribed above, which indicate that the particles are substantially notporous. Without being bound by theory, it is believed that pores createtortuous paths within the particles that can impede the flow of ions(e.g., lithium ions), particularly at a low state of charge and/or athigh discharge rates. Additionally, a higher degree of porosity cancreate higher total surface areas, which, as described above, can leadto more unwanted chemical side reactions. In some embodiments, thecarbon black particles have a ratio of STSA to BET surface area(STSA:BET ratio) greater than 0.95:1, e.g., greater than 0.96:1, orgreater than 0.97:1, or greater than 0.98:1, or greater than 0.99:1.Statistical thickness surface area is determined by ASTM D6556-10.

The carbon black particles can have a high degree of graphitization, asindicated by a high % crystallinity, which is obtained from Ramanmeasurements as a ratio of the area of the G band and the areas of G andD bands (I_(G)/I_(G+D)). In certain embodiments, the carbon blackparticles have % crystallinities (I_(G)/I_(G+D)) ranging from 35% to45%, as determined by Raman spectroscopy. The % crystallinity(I_(G)/I_(G+D)) can have or include, for example, one of the followingranges: from 35% to 43%, or from 35% to 41%, or from 35% to 39%, or from37% to 45%, or from 37% to 43%, or from 37% to 41%, from 39% to 45%, orfrom 39% to 43%, or from 41% to 45%.

A high degree of graphitization can also be indicated by lower surfaceenergy values, which can be associated with lower amounts of residualimpurities on the surface of carbon black particles, and thus, theirhydrophobicity. Without being bound by theory, it is believed that, upto a threshold purity level, purer particles can provide improvedelectrical conductivity, thereby improving the performance of theparticles. Surface energy can be measured by Dynamic Water (Vapor)Sorption (DVS) or water spreading pressure (described below). In someembodiments, the carbon black has a surface energy (SE) less than orequal to 15 mJ/m², e.g., from the detection limit (about 2 mJ/m²) to 15mJ/m². The surface energy can have or include, for example, one of thefollowing ranges: from the detection limit to 12 mJ/m², or from thedetection limit to 10 mJ/m², or from the detection limit to 8 mJ/m², orfrom the detection limit to 6 mJ/m², or from the detection limit to 4mJ/m². In certain embodiments, the surface energy, as measured by DVS,is less than 14 mJ/m², or less than 12 mJ/m², or less than 10 mJ/m², orless than 8 mJ/m², or less than 6 mJ/m², or less than 4 mJ/m², or at thedetection limit.

Water spreading pressure is a measure of the interaction energy betweenthe surface of carbon black (which absorbs no water) and water vapor.The spreading pressure is measured by observing the mass increase of asample as it adsorbs water from a controlled atmosphere. In the test,the relative humidity (RH) of the atmosphere around the sample isincreased from 0% (pure nitrogen) to about 100% (water-saturatednitrogen). If the sample and atmosphere are always in equilibrium, thewater spreading pressure (π_(e)) of the sample is defined as:

$\pi_{e} = {\frac{RT}{A}{\int_{o}^{P_{o}}{\Gamma \; {dlnP}}}}$

where R is the gas constant, T is the temperature, A is the BET surfacearea of the sample as described herein, Γ is the amount of adsorbedwater on the sample (converted to moles/gm), P is the partial pressureof water in the atmosphere, and P_(o) is the saturation vapor pressurein the atmosphere. In practice, the equilibrium adsorption of water onthe surface is measured at one or (preferably) several discrete partialpressures and the integral is estimated by the area under the curve.

The procedure for measuring the water spreading pressure is detailed in“Dynamic Vapor Sorption Using Water, Standard Operating Procedure”, rev.Feb. 8, 2005 (incorporated in its entirety by reference herein), and issummarized here. Before analysis, 100 mg of the carbon black to beanalyzed was dried in an oven at 125° C. for 30 minutes. After ensuringthat the incubator in the Surface Measurement Systems DVS1 instrument(supplied by SMS Instruments, Monarch Beach, Calif.) had been stable at25° C. for 2 hours, sample cups were loaded in both the sample andreference chambers. The target RH was set to 0% for 10 minutes to drythe cups and to establish a stable mass baseline. After dischargingstatic and taring the balance, approximately 10-12 mg of carbon blackwas added to the cup in the sample chamber. After sealing the samplechamber, the sample was allowed to equilibrate at 0% RH. Afterequilibration, the initial mass of the sample was recorded. The relativehumidity of the nitrogen atmosphere was then increased sequentially tolevels of approximately 0, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, and95% RH, with the system allowed to equilibrate for 20 minutes at each RHlevel. The mass of water adsorbed at each humidity level was recorded,from which water spreading pressure was calculated (see above). Themeasurement was done twice on two separate samples and the average valueis reported.

The carbon black particles can have a relatively low oxygen content,which can be indicative of the particles' purity and electricalconductivity properties. In some embodiments, the carbon black has anoxygen content of less than or equal to 1 wt %, or less than or equal to0.8 wt %, or less than or equal to 0.6 wt %%, or less than or equal to0.4 wt %. The oxygen content can have or include, for example, one ofthe following ranges: from 0.01 to 1 wt %, or from 0.03 to 1 wt %, orfrom 0.03 to 0.8 wt %, or from 0.03 to 0.6 wt % or from 0.03 to 0.4 wt%. The oxygen content can be determined by inert gas fusion in which asample of carbon black particles are exposed to very high temperatures(e.g., about 3000° C.) under inert gas conditions. The oxygen in thesample reacts with carbon to form CO and CO₂, which can be monitored bya non-dispersive infrared technique. The total oxygen content isreported in weight percent relative to the total weight of the sample.Various oxygen analyzers based on the inert gas fusion methods are knownin the art and commercially available, for example a LECO® TCH600analyzer.

The high structure carbon black particles can be produced by heattreating starting or “base” carbon black particles. The base carbonblack particles are available from Cabot Corporation (Billerica, Mass.)under the name CSX-960. Other base carbon black particles and methods ofmaking them are described in U.S. Provisional Patent Application No.62/500,672, entitled “Carbon Black and Rubber Compounds IncorporatingSame”, filed on May 3, 2017, hereby incorporated by reference.

As indicated above, in certain embodiments, the high structure carbonblack particles are heat-treated carbon black particles. “Heat-treatedcarbon black particles” are carbon black particles that have undergone a“heat treatment,” which as used herein, generally refers to apost-treatment of base carbon black particles that had been previouslyformed, e.g., by a furnace black process. The heat treatment can occurunder inert conditions (i.e., in an atmosphere substantially devoid ofoxygen), and typically occurs in a vessel other than that in which thebase carbon black particles were formed. Inert conditions include, butare not limited to, a vacuum, and an atmosphere of inert gas, such asnitrogen, argon, and the like. In some embodiments, the heat treatmentof carbon blacks under inert conditions is capable of reducing thenumber of impurities (e.g., residual oil and salts), defects,dislocations, and/or discontinuities in carbon black crystallites and/orincrease the degree of graphitization.

The heat treatment temperatures can vary. In various embodiments, theheat treatment (e.g., under inert conditions) is performed at atemperature of at least 1000° C., or at least 1200° C., or at least1400° C., or at least 1500° C., or at least 1700° C., or at least 2000°C. In some embodiments, the heat treatment is performed at a temperatureranging from 1000° C. to 2500° C., e.g., from 1400° C. to 1600° C. Heattreatment performed at a temperature refers to one or more temperaturesranges disclosed herein, and can involve heating at a steadytemperature, or heating while ramping the temperature up or down, eitherstepwise and/or otherwise.

The heat treatment time periods can vary. In certain embodiments, theheat treatment is performed for at least 15 minutes, e.g., at least 30minutes, or at least 1 hour, or at least 2 hours, or at least 6 hours,or at least 24 hours, or any of these time periods up to 48 hours, atone or more of the temperature ranges disclosed herein. In someembodiments, the heat treatment is performed for a time period rangingfrom 15 minutes to at least 24 hours, e.g., from 15 minutes to 6 hours,or from 15 minutes to 4 hours, or from 30 minutes to 6 hours, or from 30minutes to 4 hours.

Generally, the heat treatment is performed until one or more desiredproperties of the high structure carbon black particles (e.g., surfaceenergy, L_(a) crystallite size, L_(c) crystallite size, and/or %crystallinity) are produced. As an example, during initial periods ofheat treatment, test samples of heat treated particles can be removed,and their L_(c) crystallite sizes can be measured. If the measured L_(c)crystallite sizes are not as desired, then various heat treatmentprocess parameters (such as heat treatment temperature and/or residencetime) can be adjusted until the desired L_(c) crystallite size isproduced.

The high structure carbon black particles can be used in a variety ofenergy storage devices, such as lithium-ion batteries. As an example,the carbon black particles can be used in a cathode composition for alithium-ion battery. The cathode composition typically includes amixture of one or more electroactive materials, a binder, and aconductive aid (such as the high structure carbon blacks). As usedherein, an “electroactive material” means a material capable ofundergoing reversible, Faradaic and/or capacitive electrochemicalreactions.

In some embodiments, the electroactive material is a lithium ion-basedcompound. Exemplary electroactive materials include those selected fromat least one of:

-   -   LiMPO₄, wherein M represents one or more metals selected from        Fe, Mn, Co, and Ni;    -   LiM′O₂, wherein M′ represents one or more metals selected from        Ni, Mn, Co, Al, Mg, Ti, V, Cr, Fe, Zr, Ga, and Si;    -   Li(M″)₂O₄, wherein M″ represents one or more metals selected        from Ni, Mn, Co, Al, Mg, Ti, V, Cr, Fe, Zr, Ga, and Si (e.g.,        Li[Mn(M″)]₂O₄); and    -   Li_(1+x)(Ni_(y)Co_(1−y−z)Mn_(z))_(1−x)O₂, wherein x ranges from        0 to 1, y ranges from 0 to 1 and z ranges from 0 to 1.

In certain embodiments, the electroactive material is selected from atleast one of LiNiO₂; LiNi_(x)Al_(y)O₂ where x varies from 0.8-0.99, yvaries from 0.01-0.2, and x+y=1; LiCoO₂; LiMn₂O₄; Li₂MnO₃;LiNi_(0.5)Mn_(1.5)O₄; LiFe_(x)Mn_(y)Co_(z)PO₄ where x varies from0.01-1, y varies from 0.01-1, z varies from 0.01-0.2, and x+y+z=1; andLiNi_(1-x-y)Mn_(x)Co_(y)O₂, wherein x ranges from 0.01 to 0.99 and yranges from 0.01 to 0.99.

In other embodiments, the electroactive material is selected from atleast one of Li₂MnO₃; LiNi_(1−x−y)Mn_(x)Co_(y)O₂ wherein x ranges from0.01 to 0.99 and y ranges from 0.01 to 0.99; LiNi_(0.5)Mn_(1.5)O₄;Li_(1+x)(Ni_(y)Co_(1−y−z)Mn_(z))_(1−x)O₂, wherein x ranges from 0 to 1,y ranges from 0 to 1 and z ranges from 0 to 1; and layer-layercompositions containing at least one of an Li₂MnO₃ phase and an LiMn₂O₃phase.

In some embodiments, the electrode includes a mixture of activematerials having a nickel-doped Mn spinel, and a layer-layer Mn richcomposition. The nickel-doped Mn spinel can have the formulaLiNi_(0.5)Mn_(1.5)O₄, and the layer-layer Mn rich composition cancontain a Li₂MnO₃ or a LiMn₂O₃ phase, and mixtures thereof.

The concentration of electroactive material(s) in the electrode canvary, depending on the particular type of energy storage device. In someembodiments, the electroactive material is present in the cathodecomposition in an amount of at least 80% by weight, relative to thetotal weight of the composition, e.g., an amount of at least 90%, or anamount ranging from 80% to 99%, or an amount ranging from 90% to 99% byweight, relative to the total weight of the composition. Theelectroactive material is typically in the form of particles. In someembodiments, the electroactive particles have a D₅₀ (or median) particlesize distribution ranging from 100 nm to 30 μm, e.g., a D₅₀ ranging from1-15 μm. In other embodiments, the electroactive particles have a D₅₀ranging from 1-6 μm, e.g., from 1-5 μm.

Typically, the cathode composition further includes one or more bindersto enhance the mechanical properties of the formed electrode. Exemplarybinder materials include, but are not limited to, fluorinated polymerssuch as poly(vinyldifluoroethylene) (PVDF),poly(vinyldifluoroethylene-co-hexafluoropropylene) (PVDF-HFP),poly(tetrafluoroethylene) (PTFE), polyimides, and water-soluble binders,such as poly(ethylene) oxide, polyvinyl-alcohol (PVA), cellulose,carboxymethylcellulose (CMC), starch, hydroxypropylcellulose,regenerated cellulose, polyvinyl pyrrolidone (PVP), and copolymers andmixtures thereof. Other possible binders include polyethylene,polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonatedEPDM, styrene-butadiene rubber (SBR), and fluoro rubber and copolymersand mixtures thereof. In some embodiments, the binder is present in thecathode composition in an amount of 1 to 10% by weight.

Like the concentrations of the electroactive material, theconcentrations of the high structure carbon black particles can vary.For example, for batteries used in electric vehicles, the carbon blackamount can range from 1-2% by weight. For batteries used in plug-invehicles, the carbon black amount can range from 3-6% by weight. Forbatteries used in hybrid vehicles, the carbon black amount can rangefrom 5-10% by weight.

An electrode (e.g., cathode) composition can be made by homogeneouslyinterspersing (e.g., by uniformly mixing) the high structure carbonblack particles with the electroactive material. In some embodiments,the binder is also homogeneously interspersed with the carbon blackparticles and electroactive material. The electrode composition can takethe form of a paste or a slurry, in which particulate electroactivematerial, carbon black, and binder (if present) are combined in thepresence of one or more solvents. Exemplary solvents include, e.g.,N-methylpyrrolidone (NMP), acetone, alcohols, and water. The componentsof the electrode composition can be combined in the solvent in any orderso long as the resulting mixture is substantially homogeneous, which canbe achieved by shaking, stirring, etc. In certain embodiments, theelectrode composition is a solid resulting from solvent removal from thepaste or slurry.

It has been found that the high structure carbon black particles arecapable of providing processability benefits. For example, the highstructure particles are capable of providing good dispersability, whichenhances the uniform distribution of fine particles in the composition.“Dispersability,” as used herein, is defined as the particle size (orD₅₀, by volume) achieved in a composition having of 5.7 wt % carbonblack and 4.3 wt % PVDF (Kynar® HSV 900 polyvinylidene fluoride-basedresin with molecular weight of 900,000, from Arkema) in NMP after 20minutes of milling in a SPEX® 8000M mixer/mill. In some embodiments, thehigh structure carbon black particles have a dispersability of about onemicron.

Surprisingly, the high structure carbon black particles are also capableof providing a paste having relatively low viscosity (or at least,similar to conductive carbons currently used by the industry). Thiscapability is rather unexpected since highly structured additivestypically lead to formulations with high viscosity. Having a paste withlow viscosity allows easier interspersion, more compositionaluniformity, higher concentrations (i.e., higher amounts of activematerials), manufacturing flexibility, and lower costs (e.g., due tolower processing energy needed). Viscosity, as used herein, is definedas the viscosity at a shear rate of 50 s¹ for a paste having NCM111:carbon black:PVDF binder=93:4:3 in NMP at 68 wt % solids prepared bymilling in a SPEX® 8000M mixer/mill for 30 minutes. “NCM 111” is alithium nickel cobalt manganese oxide (Ni:Co:Mn=1:1:1) batteryelectroactive material from TODA Kogyo Corp. (NME-1100). In someembodiments, the high structure carbon black particles can provide apaste having a viscosity of less than 20 Pa-s, for example, less than 18Pa-s, or less than 16 Pa-s.

In some embodiments, an electrode is formed by depositing the paste ontoan electrically conducting substrate (e.g., an aluminum currentcollector), followed by removing the solvent. In certain embodiments,the paste has a sufficiently high solids loading to enable depositiononto the substrate while minimizing the formation of inherent defects(e.g., cracking) that may result with a less viscous paste (e.g., havinga lower solids loading). Moreover, a higher solids loading reduces theamount of solvent needed. The solvent is removed by drying the paste,either at ambient temperature or under low heat conditions, e.g.,temperatures ranging from 20° to 100° C. The deposited cathode/currentcollector can be cut to the desired dimensions, optionally followed bycalendaring.

The formed electrode can be incorporated into a lithium-ion batteryaccording to methods known in the art, for example, as described in“Lithium Ion Batteries Fundamentals and Applications”, by Yuping Wu, CRCpress, (2015).

In other embodiments, the high structure carbon black particles are used(e.g., incorporated) in electrodes of other energy storage devices, suchas, primary alkaline batteries, primary lithium batteries, nickel metalhydride batteries, sodium batteries, lithium sulfur batteries, lithiumair batteries, and supercapacitors. Methods of making such devices areknown in the art and are described, for example, in “Battery ReferenceBook”, by TR Crompton, Newness (2000).

EXAMPLES Example 1

This example describes the preparation of a highly structured carbonblack by heat treating a base carbon black. The base carbon black was afurnace carbon black (CSX-960 from Cabot Corporation) that had BETsurface area (BET SA) of 99 m²/g, an oil absorption number (OAN) of 252ml/100 g, a surface energy (SEP) of 16 mJ/m², an L_(a) crystallite sizeof 15 Å, a crystallinity of about 26%, and an L_(c) crystallite size ofabout 15 Å. The base carbon black was heat treated at severaltemperatures ranging from 1300° C. to 1600° C. in a box oven under aninert nitrogen atmosphere for 2 hours. The material was then ground witha lab mill (Perten 3710) to a tap density of about 100 g/L.

Table 1 summarizes the physical characteristics for the base carbonblack (CSX-960) and the heat treated samples (Samples A-D). With theheat treatment, there were minor changes to the particle morphology asindicated by BET surface area and OAN. However, the size of the carboncrystallite domains (L_(a) and L_(c)), particle crystallinity andsurface energy changed significantly. The heat treated carbon blackshave, what is believed to be, a novel combination of intermediatesurface area, high particle structure, moderate size of thecrystallites, and intermediate size of the primary particles.Surprisingly, as illustrated by the following examples, carbon blackswith these morphological and physical characteristics demonstrated notonly significant performance improvements to lithium-ion batteriesincluding such carbon blacks but also maintain excellent processabilityproperties, for instance, the ease of dispersion and low pasteviscosity, which are significant for the battery manufacturers sincethey are able to use such high structure conductive carbon black withthe same manufacturing process without significant process adjustmentsor upgrades.

TABLE 1 Physical characteristics of carbon blacks obtained after heattreatment Oven BET OAN SEP Crystal- Temperature, SA (ml/ (mJ/ L_(a)linity L_(c) Sample (° C.) (m²/g) 100 g) m²) (Å) (%) (Å) Base n/a 99 25216 15 25.9 14.9 A 1300 96.4 244 ≦3 24.6 36.2 18 B 1400 95.3 247 ≦3 27.138.4 19.5 C 1500 94.3 246 ≦3 31 41.6 22.7 D 1600 94.5 244 ≦3 33 43 25.4

Example 2

This Example describes dispersability testing of two conductive carbonblacks (CB) and an acetylene black (AB), namely, the CSX-960 base carbonfrom Example 1, Sample B from Example 1, and a commercially availableacetylene black (Sample E). Characteristics for these carbons are shownin Table 2. For Sample E, characteristics designated with an asterisk“*” are from public sources, such as, “Acetylene Black as ConductiveAdditive for Lithium-ion Batteries—Approach for Battery ConductiveAdditives at Denka”, Advanced Technology Workshop, The Carbon Society ofJapan, Kyoto, Japan 2015.06.05. A solution was prepared containing 10 wt% Kynar® HSV 900 polyvinylidene fluoride-based resin (PVDF, by Arkemawith molecular weight of 900,000) in N-Methyl-2-pyrrolidone (NMP, SigmaAldrich >99% HPLC grade). A dispersion was prepared by combining 2.29 gof a carbon black (or acetylene black), 17.1 g of the 10 wt % PVDFsolution in NMP, and 20.61 g of NMP in 55 mL tungsten carbide grindingvial along with two 11.2-mm-diameter tungsten carbide balls. Thetungsten carbide grinding vial and balls are available from SPEX®SamplePrep (part #8004). The dispersion was milled in a SPEX® 8000Mmixer/mill for 20 minutes. Once the milling was completed, a smallamount of dispersion was taken and diluted with NMP in 1:10 wt % ratio.Particle size measurements were performed using a Horiba LA-950V2Particle Size Analyzer and its software.

TABLE 2 Characteristics of conductive carbons subjected todispersability testing BET OAN SEP Crystal- SA (ml/ (mJ/ L_(a) linityL_(c) P_(size) Sample Type (m²/g) 100 g) m²) (Å) (%) (Å) (nm) Base CB 99252 16 15 25.9 14.9 18 B CB 95.3 247 ≦3 27.1 38.4 19.5 18 E AB 66  220*2 38 46.7 35*   35*

FIG. 1 depicts the particle size distribution of the conductive carbonsprepared as described above, and Table 3 summarizes the dispersability(D₅₀ by volume for each carbon. As shown by the lower particle sizedistributions, for the given milling conditions, both the base carbonand Sample B showed better dispersability versus the comparativecommercial carbon additive.

TABLE 3 Results of material dispersability and paste viscosity testingDispersability Paste viscosity Sample (μm) (Pa · s) Base 0.67 9.4 B 0.917.5 E 2.6 18.25

Example 3

This Example describes a method for preparing pastes including anelectroactive material and a conductive carbon additive from Example 2,and summarizes the viscosities of the resulting pastes.

A solution containing 10 wt % Kynar® HSV 900 polyvinylidenefluoride-based resin (PVDF, by Arkema with molecular weight of 900,000)in N-methyl-2-pyrrolidone (NMP, Sigma Aldrich >99% HPLC grade) wasprepared. A mixture was then prepared by combining 1.09 g of aconductive carbon additive, 8.2 g of the 10 wt % PVDF solution in NMPsolution, 25.29 g lithium nickel cobalt manganese oxide (“NCM 111”,i.e., Ni:Co:Mn=1:1:1, a battery active material from TODA Kogyo Corp.(NME-1100)), and 5.42 g of NMP in a 55 mL tungsten carbide grinding vialalong with two 11.2-mm diameter tungsten carbide balls. The mixture wasmilled in a SPEX® 8000M mixer/mill for 30 minutes to prepare a paste.Once the milling was completed, approximately 2-3 mL of the paste wasused to perform rheological characterization using an AR-2000 rheometer(TA Instruments). Paste viscosity was measured at a shear rate of 50s⁻¹.

Table 3 summarizes the paste viscosity for each carbon additive. Asshown, the base carbon and Sample B had lower or slightly lower pasteviscosities versus the comparative commercial carbon additive. Theresults of this viscosity and dispensability evaluation suggest that theconductive carbons described herein can be readily used with existingmanufacturing process without significant adjustments.

Example 4

This Example describes a process of making a cathode including variousconductive carbon additives (CCA), and the results of an evaluation ofelectrode sheet resistance for various compositions.

Coin-Cell Preparation:

Electrodes were prepared by mixing a slurry of 10 wt % Kynar® HSV 900polyvinylidene fluoride-based resin (PVDF, by Arkema with molecularweight of 900,000) in N-methyl-2-pyrrolidone (NMP, Sigma Aldrich >99%HPLC grade), carbon black (CB), active material (NCM 111, approximately7 microns D₅₀ particle size) and NMP. The slurries were mixed for 30minutes with a SPEX® 8000M mixer/mill and two tungsten carbide mediaballs. Formulations, coated weight, and total solids loadings of theslurries are reported in Table 4:

TABLE 4 Slurry formulations tested Formulation Slurry total Coateddensity NCM 111:CB:PVDF % solids mg/cm² 96.5:2:1.5 70 10 93:4:3 68 10

The electrode slurries were coated on aluminum foils using an automateddoctor blade coater (Model MSK-AFA-III from MTI Corp.). The NMP wasevaporated for 20 minutes in a convection oven set at 80° C.Fifteen-millimeter-in-diameter discs were punched for coin-cellpreparation and dried at 110° C. under vacuum for a minimum of 4 hours.Discs were calendered at 2.5 g/cc with a manual roll press, andassembled into 2032 coin-cells in an argon-filled glove box (M-Braun)for testing against lithium foil. Glass fiber micro filters (WhatmanGF/A) were used as separators. The electrolyte was 100 microliters ofethylene carbonate-dimethyl carbonate-ethylmethyl carbonate(EC-DMC-EMC), vinylene carbonate (VC) 1%, LiPF₆ 1M (BASF). Fourcoin-cells were assembled for each formulation tested. Reportedcapacities are averages of the four coin-cells, normalized in mAh/g ofactive cathode mass. Additionally, thicker electrodes (coated density=30mg/cm²) with NCM(111):CB:PVDF=96.5:2:1.5 were prepared to evaluateelectrical properties and fast charging capability characteristics ofthe cells containing the electrodes. These electrode were calendered at3 g/cc. The protocol for assembly into 2032 coin-cell was identical todescribed above.

Electrode Sheet Resistance Measurements:

Sheet resistance of coated electrodes was measured with a Lucas Lab 302four-probe stand and an SP4 probe head connected to the rear of aKeithley 2410-C source meter. Measurements were performed in a two-wireconfiguration mode because it was found that four-wire measurements ledto a strong contribution of substrate conductivity. The reported valuesare direct ohm readings from the instrument, at a current of 0.1 mA, anda cathode calendered density of 2.5 g/cc.

Electrode Through Plane (Bulk) Conductivity Measurements:

Bulk conductivity for 15-mm-diameter electrode discs coated on aluminumwas measured with a drop gauge (Sylvac, 0.001 mm precision) in which DCresistance was measured between an aluminum current collector pressedagainst a stand (insulated from the gauge), and a contact made on thetop of the electrode coating with a 0.4-cm²-cylindrical carbide tip(Carbide probes Inc.) applied at 10 psi (300 g weight) against thesample. The resistivity of electrode between tip and base was measuredwith a Keithley 2410-C Source Meter. Bulk conductivity (S/cm) of thesamples was calculated by the formula S/cm=(1/R)*(1/s) where 1 is theelectrode thickness minus current collector (in cm) and s is the contactarea (0.4 cm²).

As shown in FIG. 2, the heat treatment of the base CSX-960 carbon made apositive impact on the electrode resistivity. The electrodes havingSample B, C and D showed the lowest resistivity at 2 wt % carbonadditive loading (about 2000 Ohm), and demonstrated substantialimprovement versus the commercial additive (Sample E). At 4 wt % carbonadditive loading, all heat treated samples derived from the base carbonshowed a resistivity of about 200-250 Ohm, which was significantlybetter than the resistivities for the base black and the commercialadditive Sample E (generally in 550-700 Ohm range).

As shown from the bulk conductivity measurements (Table 5 below), SampleB showed consistently better electrical (volume) conductivity in both“thin” (10 mg/cm²) and “thick” (30 mg/cm²) electrodes. Once again, therewas a significant enhancement in the electrical conductivity of CSX-960after heat treatment. Sample B was about 4 times more conductive thancommercially used acetylene black (Sample E) in the “thin” electrodesand about 2 times more conductive in the “thick” electrodes at the sameloading and calendaring density

TABLE 5 Bulk conductivity results Calendering Bulk Formulation Arealoading density conductivity Sample NCM:CB:PVDF mg/cm² g/cc S/cm CSX-96093:4:3 10 2.5 4.62 * 10⁻⁴ Carbon B 93:4:3 10 2.5 1.91 * 10⁻³ Carbon E93:4:3 10 2.5 4.79 * 10⁻⁴ Carbon B 96.5:2:1.5 30 3.0 6.50 * 10⁻⁴ CarbonE 96.5:2:1.5 30 3.0 3.55 * 10⁻⁴

Example 5

This Example summarizes the evaluation results from testing variousconductive carbon additives in lithium-ion coin cells.

C-Rate Capability Measurements:

Coin cells were tested on a Maccor Series 4000 battery cycler accordingto the following procedure: Two C/5 charge-discharge formation cycles ina 2.8-4.3 voltage window, with constant voltage charging step up toC/20, then C/2 charging with constant voltage charging step up to C/20and C/5, C/2, 1C, 2C, 3C, 4C, 5C, 7C, 10C, 15C, and 20C discharge rates.1C rate (h⁻¹) is defined as the current to discharge the cell in 1 hr.Typically, four individual coin cells were assembled and tested for eachconductive carbon additive loading. The evaluation results wereaveraged.

FIG. 3 shows discharge curves of for coin cells with various conductivecarbon additives (CCA) at 2 wt % loading as a function of C-rate. Thecathode composition is NCM 111:CCA:PVDF=96.5:2:1.5.

FIG. 4 shows discharge curves for coin cells with various conductivecarbon additives at 4 wt % loading as a function of C-rate. The cathodecomposition is NCM 111:CCA:PVDF=93:4:3.

FIGS. 3 and 4 indicate that cathode specific capacity is preserved athigher rates of discharge current when Samples A-D are used, at either 2or 4 wt % loading. This indicates that the cells with Samples A-D haveimproved continuous discharge power capability, with Samples C and Dhaving performed the best in this test. This feature may enable smallbattery size requirements to achieve specific power targets, and may bebeneficial for cranking large or high compression diesel engines, suchas those used in trucks.

Hybrid Pulse Power Capability (HPPC) Measurements:

After evaluating the C-rate capability of the cells, they were testedfor HPPC. A full description of the HPPC test can be found in US DOEVehicle Technologies Battery Test Manual for Plug-In Hybrid ElectricVehicles, 2008, Idaho National Lab INL/EXT-07-12536.

Fully recharged cells were submitted to 5C, 10 s discharge currentpulses, 40 s rests, 3.75C, 10 s charge current pulses, by 10% state ofcharge decrements achieved by 1C discharge steps of 6 minutes. From thistest, the DC-IR and ionic discharge resistances were calculated usingOhm's law. DC-IR is based on the instant Ohmic drop, and ionicresistance is the end of pulse resistance minus instant Ohmic drop.

Both DC-IR and ionic resistance have been measured at 2 wt % and 4 wt %CCA loading and are shown on FIGS. 5-8. FIG. 5 is a plot of the DC-IRcomponent of the total resistance as a function of state of charge forcells having different carbon conductive additives at 2 wt % loading(NCM 111:CCA:PVDF=96.5:2:1.5). FIG. 6 is a plot of the ionic componentof the total resistance as a function of state of charge for cellshaving different carbon conductive additives at 2 wt % loading (NCM111:CCA:PVDF=96.5:2:1.5). FIG. 7 is a plot of the DC-IR component of thetotal resistance as a function of state of charge for cells havingdifferent carbon conductive additives at 4 wt % loading (NCM111:CCA:PVDF=93:4:3). FIG. 8 is a plot of the ionic component of thetotal resistance as a function of state of charge for the cells havingdifferent carbon conductive additives at 2 wt % loading (NCM111:CCA:PVDF=93:4:3).

As shown in FIGS. 5-8, at 2 and 4 wt % CCA, Samples B, C and D have thelowest DC-IR, while the ionic resistance at low states of charge is alsolower for these samples. This indicates better discharge pulse powercapability over all states of charge, which is especially useful forvehicle acceleration in automotive application. The fact that electronicionic resistances are lower at lower states of charge enables anincrease in the useful range of battery state of charge. This may, forinstance, enable maintaining of the start-stop function of a vehicle insituations where the battery is at a low state of charge.

Example 6

This Example summarizes the evaluation results from the fast chargingtest for Sample B and Sample E.

Fast charging test was performed on half coin-cells (withNCM(111):CB:PVDF=96.5:2:1.5 cathode, 30 mg/cm² loading and calendered to3 g/cc) by charging cells in 1 h (1C) and 20 min (3C) rates, andmeasuring their discharge capacity in 2 h discharge rate. Althoughgraphite anodes are generally limiting fast charging capability ofLi-ion batteries, this test is useful to understand the electrochemicaland transport properties of the cathodes.

As shown in FIG. 9, the cells comprising carbon B can be partiallycharged at 20 min rate (3C), while carbon E cannot. At 1C charging rate,cells comprising carbon B can be charged to 135 mAh/g, while thosehaving currently used carbon E can only be charged to 115 mAh/g. If thefast charging limitations of graphite anodes are overcome in the future(or a different anode is used), conductive additive B may enable fastercharging capability to a lithium ion battery, which is of significantimportance to both industry and consumers.

The use of the terms “a” and “an” and “the” is to be construed to coverboth the singular and the plural, unless otherwise indicated herein orclearly contradicted by context. The terms “comprising,” “having,”“including,” and “containing” are to be construed as open-ended terms(i.e., meaning “including, but not limited to,”) unless otherwise noted.Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention unless otherwise claimed. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential to the practice of the invention.

All publications, applications, ASTM standards, and patents referred toherein are incorporated by reference in their entirety.

Other embodiments of the present invention will be apparent to thoseskilled in the art from consideration of the present specification andpractice of the present invention disclosed herein. It is intended thatthe present specification and examples be considered as exemplary onlywith a true scope and spirit of the invention being indicated by thefollowing claims and equivalents thereof.

What is claimed is:
 1. An electrode for an energy storage device,comprising: carbon black particles having (a) a Brunauer-Emmett-Teller(BET) surface area ranging from 70 to 120 m²/g; (b) an oil absorptionnumber (OAN) ranging from 180 to 310 mL/100 g; (c) a surface energy lessthan or equal to 15 mJ/m²; and (d) either an L_(a) crystallite size lessthan or equal to 29 Å, or a primary particle size less than or equal to24 nm.
 2. The electrode of claim 1, wherein the carbon black particleshave both an La crystallite size less than or equal to 29 Å, and aparticle size less than or equal to 24 nm. 3-11. (canceled)
 12. Theelectrode of claim 1, wherein the carbon black particles have a particlesize less than or equal to 24 nm.
 13. (canceled)
 14. (canceled)
 15. Theelectrode of claim 1, wherein the carbon black particles have a surfaceenergy less than or equal to 10 mJ/m².
 16. (canceled)
 17. The electrodeof claim 1, wherein the carbon black particles have a % crystallinity(I_(G)/I_(G+D)) less than or equal to 45%, as determined by Ramanspectroscopy.
 18. (canceled)
 19. The electrode of claim 1, wherein thecarbon black particles have an oxygen content of less than or equal to 1wt %.
 20. The electrode of claim 1, wherein the carbon black particleshave a dispersability of less than one micron (D₅₀ by volume).
 21. Theelectrode of claim 1, wherein the carbon black particles have a ratio ofstatistical thickness surface area to Brunauer-Emmett-Teller surfacearea (STSA:BET) greater than 0.95:1.
 22. (canceled)
 23. (canceled)
 24. Acomposition, comprising: carbon black particles having (a) aBrunauer-Emmett-Teller (BET) surface area ranging from 70 to 120 m²/g;(b) an oil absorption number (OAN) ranging from 180 to 310 mL/100 g; (c)a surface energy less than or equal to 15 mJ/m²; and (d) either an L_(a)crystallite size less than or equal to 29 Å, or a primary particle sizeless than or equal to 24 nm.
 25. The composition of claim 24, in theform of a dispersion, a dry powder, or a paste.
 26. The composition ofclaim 24, in the form of a paste having a viscosity of less than 20Pa-s.
 27. The composition of claim 24, further comprising anelectroactive material. 28-47. (canceled)
 48. Carbon black particleshaving (a) a Brunauer-Emmett-Teller (BET) surface area ranging from 70to 120 m²/g; (b) an oil absorption number (OAN) ranging from 180 to 310mL/100 g; (c) a surface energy less than or equal to 15 mJ/m²; and (d)either an L_(a) crystallite size less than or equal to 29 Å, or aprimary particle size less than or equal to 24 nm. 49-90. (canceled)